Adaptive digital filtering is a widespread technique in many applications. In some applications such as acoustic echo cancellation or active noise control, very large adaptive digital filters are used in a system identification context. In addition, subband techniques for adaptive digital filters have been proposed to improve their convergence. On the other hand, discrete wavelet transform is one of the methods of signal processing, and multiresolusion analysis is the well-known method of them. This multiresolusion analysis forms filter banks and can be used for the subband filters. However, it has a demerit of lack of shift invariance, and the adaptive digital filter using it has little advantage of convergence. Therefore, in this paper, redundant discrete wavelet transform is proposed to be used for the subband adaptive digital filter. Thereby, many kinds of orthogonal wavelets, which have been prepared for the discrete wavelet transform, can be used for the widespread adaptive digital filters. In addition, some simulations are given to show the effectiveness of the proposed method in the system identification context, moreover, acoustic echo cancellation with speech signals is simulated.

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Electrode catheter ablation is one of the remedies for atrial fibrillation (AF) which is a kind of heart disease. Catheter ablation is an operation which suppresses AF by the insertion of a catheter into the heart and burning the parts causing premature atrial contractions (PAC). However, generally, the operation takes several hours since the parts causing PAC remain to identified and reoperations are frequently required. If only the parts causing PAC can be detected, early and accurate operation would be possible. This paper describes discovering the parts causing the PAC from catheter electrocardiograms (C-ECGs) by using a novel analytical method to detect the signal derived from the heart. Patients were done the catheter ablation, and the catheter electrocardiogram was measured. In this paper we show the first, the parts causing the PAC from C-ECGs by translation error using Wayland test and Double-Wayland test. Second, it is shown that the rule of the measurement signal can be distinguished from translation error, and finally, these methods can be applied to the detection of the parts causing PAC from patient's C-ECGs.

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This paper deals analytically and experimentally with the design of a dynamic absorber to quench squeal generated in car disc brakes. Firstly, the design of the dynamic absorber was investigated to quench the frictional vibration due to Coulomb friction of a two-degree-of-freedom block system simplifying disc brakes. The agreement between the analytical and experimental results on the optimal design of the dynamic absorber was confirmed. Next, the optimal design was applied to the disc brake. It was found by the analysis and experiments that the natural frequency of the dynamic absorber should be tuned near the squeal frequency and the damping of the dynamic absorber was not needed to quench squeal. Hence, the optimum design of the dynamic absorber to quench self-excited vibration caused by the asymmetry of stiffness matrix of the system was quite different from that of the forced vibrations.

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This investigation deals with the rocking response of a rigid block subjected to 1-dimensional harmonic excitations with the minute changes of the system parameters, such as the frictional coefficient. This paper is part one of the examination about the effects by those minute changes and is related with the minute change of friction coefficients. The numerical analysis program is developed to solve the nonlinear equations of motion governing the rocking motion of a rigid block subjected to horizontal base excitation. Natural change of the frictional coefficient is realized by the random numbers with normal probability distribution. The analytical results showed that the rocking responses are very sensitive to small changes of the friction condition between the block and the base and their effect is also large. The minute change of the friction coefficients makes the rocking response unstable and the distribution shape of rocking response change massively. Those effects by the dynamic change of the friction coefficients become a testimony of the non-reappearance on the experimental rocking responses.

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This paper describes a new design method for optimizing the thickness distribution of a multilayered structure located on the coupling surface between a structure and an acoustic cavity. The design method is based on the concept of a topology optimization method incorporating a transfer matrix for the multilayered structure that includes a poroelastic media layer. The one-dimensional transfer matrix adopted here is an approximate representation addressing vibro-acoustic effects inherent in a multilayered structure over a range of low frequencies, and balances calculation times and desired accuracy. In this study, the problem of minimizing the acoustic pressure within the cavity over the prescribed frequency range is formulated under the constraint of the total weight of the design domain. The thickness of the poroelastic media layer at each nodal point is chosen as the design variables. Numerical results show that acoustic response is significantly reduced by an optimal thickness distribution having a total weight equal to or less than that of the initial thickness.

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In this paper, two novel vibration suppression methods based on perfectly inelastic collision are developed for undamped vibration systems with unknown parameters. One is the perfect vibration suppression method by just two collisions, and the other is the asymptotic vibration suppression method which provides higher effects than one in the previous work. Also the proposed methods are applied to the problem on reduction of residual vibration in stacker cranes. In order to confirm the effectiveness of the proposals, several experiments are explored.

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This paper deals with development of new isolation device by using friction force. This isolation device carries out reduction of horizontal relative displacement by using friction force. The isolation device uses a slope plate. The Friction force acts on the slope plate. The restoring-force is given to the isolation device from the compression spring attached to the base. In the equation of motion of analytical model, the friction force changes in proportion to displacement. The restoring-force is also proportional to displacement. The restoring-force always works in the direction of a center. Therefore, the friction force and restoring-force are proportional to displacement. Simulation analysis is calculated on various conditions using the analysis model. Condition reducing both response acceleration and displacement effectively is examined. Furthermore, an experiment is conducted using the experimental model. The experimental results are compared with analysis results. The performance of the isolation device is examined. The validity of the performance is shown.

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This paper proposes a method to identify mass and stiffness matrices of structures. The mass and stiffness matrices of finite-elements have mass and stiffness distributions. Therefore, the proposed method identifies mass and stiffness matrices to improve the mass and stiffness distributions of the original model to approach those of the real structures. The mass and stiffness matrices of finite-elements are divided into several groups considering vibration modes of structures. A group is represented by a sparse matrix (grouped matrix) with non-zero values at only degrees of freedom in the group. Mass and stiffness matrices are modified group by group. The objective function to be minimized is the sum of each norm of difference between analytical and identified group matrices. A numerical example is given to show the effectiveness of the method.

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Inflatable structures are being examined these days as a new structural design paradigm to realize larger and lighter space structures. In designing such large and flexible space structures, the modal parameters including natural frequencies and mode vectors are important. However inflatable structures are liable to bring about the shape imperfection since their shapes may be changed by the pressurization and condition of inflation gas. In this study, in order to evaluate how the shape imperfections affect the modal parameters, the inflatable parabolic antenna structures, those have various shape imperfections, were analyzed. From the results of the analysis, it was found that some shape imperfections affect the natural frequencies and mode vectors significantly. This paper shows the relationship between the shape imperfection and the modal parameter of thin inflatable parabolic antenna and design methods of such inflatable structure based on the analysis results.

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This paper examines a method for the design of a real-time filter for extrcating a desired modal cluster, which is decomposed on a two-dimensional frequency domain. At first, the realization method of modal cluster decomposition was revisited. Then, in order to extract the desired modal cluster on real-time, we derived a design method of a time domain filter based on a theory for two-dimensional FIR filter. This filter computes the simple summation of current signals for a spatial direction, and hence there is no time delay to extract the signal of a desired modal cluster. As a numerical example, it was shown that the real-time filtering of the desired modal cluster can be successfully realized with low computational cost and without time delay.

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This paper studies the oil whip of an elastic rotor supported in tilting-pad journal bearings experimentally and theoretically. Oil whip was found to occur in a test rig with the non-pivotable bearing seat which produces the angular oil film coefficients, while the rotor remained stable up to the maximum shaft speed of the test rig with the pivotable bearing seat. The theoretical analyses find that oil whip of tilting pad journal bearings is caused by different mechanisms, depending on pad preload factor and bearing seat type. Predictions agree well with the observed behavior of stability threshold shaft speeds qualitatively, although the quantitative agreement needs to be improved.

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A wave absorption control of beam near fixed boundary by finite difference (FD) approach is presented. The FD equation of motion of the node under the influence of the boundary condition is compensated to be the same as that of the inner node free from the boundary condition with respect to the propagation characteristic solution by control. Then, no wave reflection occurs ; the fixed boundary condition virtually disappears. The control strategy consists of a real-time convolution integral of the measured displacement and the transfer function that is obtained by the inverse Laplace transformation of the frequency domain control transfer function. We confirmed the effectiveness of the wave controller by the time domain simulation on both FD system and distributed one as well as the frequency domain response calculation. The FD characteristic solution is qualitatively different from the distributed one, which gives the real time controller without applying the curve-fitting technique on the frequency-domain control transfer function.

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Power-assist system technology and its applications to manufacturing systems have attracted special interest recently. For example, an automobile assembly process utilizing a power-assist system has been proposed by Yamada, et al. Many power-assist systems for industrial uses possess simple power-assisting function only. Conveyance of controlled objects is generally processed by another system. Then, the author has studied on the positioning method of a cart with motor by means of a smooth switching from the servo access control for the conveyance function to the impedance control for the power-assisting function. The nonstationary optimal control method and the nonstationary impedance control law are applied to obtain the smooth switching. However, the optimal control method requires the offline calculations for generating time-varying feedback gains. If we take parameter variations in real problems into account, this characteristic is inconvenient. To realize adaptive control for the variations, this study introduces the adaptive nonstationary control (ANSC) technique proposed by the author instead of the optimal control method.

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Performance of a human size humanoid robot is strictly limited by performance of the motor. The progress of a motor has not been remarkable compared with the progress of electronics. Therefore, the great progress of the performance of the motor cannot be expected, at least in the present circumstances. A humanoid robot Saika-4 is developed aiming to break through the limitation by using a gravity compensation mechanism. The mechanism is expected to reduce the joint torque of the legs required to support the gravitational force of the whole body. This paper verifies effectiveness of the gravity compensation mechanism performing preliminary experiments.

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In this paper we deal with a global optimal design of dynamic parameters of robot manipulators. The dynamic characteristic of robot manipulators is uniquely determined by base parameters, which are functions of physical parameters, e.g., the mass, the moment of inertia and the damping, etc. of each link, not by those physical parameters themselves. Using the fact that the equation of motion of manipulators generally becomes an affine function on base parameters we propose an LMI based optimal design method of base parameters of robot manipulators. We minimize the energy which is repuired to achieve a given task of manipulators. The proposed design method guarantees the global optimality of optimized base parameters. A design example is shown in the case of an optimal design of base parameters of a planar two-link manipulator which is controlled by computed torque method.

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WT-5 (Waseda Talker No. 5), a new anthropomorphic talking robot have been developed with novel vocal cords based on human biomechanical structure. The mechanical vocal cord model has vocal folds with hollow to reproduce layer structure of human vocal cords. The vocal cords are formed by using the thermoplastic rubber “Septon”, available from Kuraray Co. Ltd., which has similar elasticity to human tissue. The vocal cords self-oscillate driven by an air flow exhausted from a mechanical lung in similar manner to a human. With new mechanisms, the robot produces natural sounding voices closer to those of a human.

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In order to survive in complex natural environments, living organisms have been genetically acquiring various algorithms. Recently, the concept of Software Biology has been propoed, in which the algorithms of living organisms are considered as a kind of software that could be utilized for robot control. We have proposed the computer model of Paramecium, Virtual Paramecium, based on biological knowledge. Virtual Paramecium can approximately realize the chemotatic behavior of actual Paramecium. In this paper, we report the results obtained when a mobile robot is controlled using Virtual Paramecium, and confirm the effectiveness of the biomimetic control based on the information processing algorithm of living organisms.

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This paper deals with development of a passive/active unified actuator and it's application to a biped walking robot. In order to implement efficiency and environmental adapting ability to a biped walking robot, it is required to combine passive walking and active one. Thus, a passive/active unified actuator that has a torque detector and is actively controlled with zere torque feedback control was developed in this paper. Proposed control scheme includes the passive walking period and the active walking one. In the passive walking period, the self-excited walking control is employed to control the swing leg.

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This paper describes an experimental system for evaluating the sitting posture of human. This system will be able to be used to make a custom-made chair. A model for the effective support of the upper part of a human is proposed. The upper part is supported by five blocks of the chair back. Each block moves in two dimensional space of horizontal plane around the back bone of the human and is supported by an imaginary spring and an imaginary damper. This proposed model is realized by the impedance control used in the control of robots. The experimental system is developed and the model is implemented. Two types of experiment are performed and the effectiveness of the developed system is shown.

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In the neurosurgery of brain tumor, patients' life after surgery crucially depends on completeness of malignant glioma resection. For decades, Photo-Dynamic Diagnosis using some oncotropic dyes (sensitizers) has been being improved as a surgical navigation system. In another field of medical diagnosis, a ratio metric technique, e.g. fluorescence ratio imaging, was applied to tumor detection, in which not only fluorescence from sensitizer, but also intrinsic auto-fluorescence were used to diagnose tumor lesions. However, it has never developed exhaustively in terms of signal noise ratio and resolution with system configuration, especially when applied to brain tumor boundary detection. In this study, in order to demarcate the brain tumor, “2-Color Photo-Dynamic Diagnosis System”, based on fluorescence ratio imaging, was constructed with higher sensitivity and resolution. This real time surgery navigating system, consisted of two CCDs and spectroscopic adaptor, can take better account of fluorescence spectroscopic characteristics. This was experimentally applied to brain tumor detection. Consequently, it was quantitatively confirmed that the contrast between tumor lesions and normal tissue could be enhanced. The present system was clarified to be effective to brain tumor monitoring and surgical delimitation.

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We investigated the effects of aroma of trees on active safety during car driving in a driving simulator. In this study, we mainly analyzed the fluctuation of driver's EEG, frequency of eye blinking and vehicle maneuver, with respect to fatigue reduction by supplying Alpha-pinene. We clarified that Alpha-pinene which is one of aroma of trees is useful to minimize the fatigue level of drivers and to keep the safety time headway to the preceding vehicle. We also analyzed the relation between the density of Alpha pinene and effectiveness in terms of reducing fatigue level. One of the results shows that supplying Alpha pinene becomes more effective as the density of that is increased, only in a condition that the annoyance level through olfactory stimulus is low. We consider that both of the annoyance level and the density of Alpha pinene operates on the effectiveness to reduce the fatigue level of driver.

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A deterministic methodology for the safety of machinery was established in a series of international standards (ISO and IEC). The methodology, being implicitly ensured by the well-tried safety principle, takes effect for the deductive prevention of the accidents originated from the hazards of machinery. In this study, in order to confirm the achievement of high preventability by obeying the conception of the safety of machinery, a data base has been constructed for the 1266 occupational accidents of damage which occurred from 1998 to 2000 in the manufacturing industry in Japan. The ISO 12100 and 14121 are adopted as a standard of the methodology to conduct the technical evalution for foreseeability and avoidability of the accidents in the data base. The preventability has been predicated on a matrix of foreseeability evaluated by the identification of the hazards and avoidability evaluated by the achievement of adequate risk reduction. The analytical result shows that 80% of accidents would have been prevented if the methodology were applied for the general hazards as specified in clause 4, ISO 12100-1. The percentage rises up to 94% when the data are confined to the mechanical hazards. These facts indicate the effectiveness of the deterministic methodology of the safety of machinery as a priori prevention of the machinery accidents.

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This paper deals with the radiated noise of strain wave gearing, which is a kind of K-H-V type planetary gears having features of lightweight and high reduction ratio. The vibration of Flex Spline (F/S), which is the element of strain wave gearing and has a thin circular cup, is considered as a main factor of the noise. The magnitude of sound power is expected to become large in proportion to the square of the amplitude of displacement of F/S in the radial direction theoretically. The displacements of 3 kinds of models are calculated using FEM. The vibration of F/S and the sound power are measured using the F/S fixed type experiment apparatus. It is confirmed that the relation between the vibration of F/S and the sound power are agreed well to the theory and the vibration of the F/S causes the radiated noise mainly. Moreover, the radiated noise with changing a rotary speed, a loaded torque and an assembly error are measured and examined. The influence of rotary speed and torque is characterized by dependence of the deformation of F/S. The noise become large with the increase of the assembly error, but the amplitude of displacement is not increased. This is analyzed by a resonance between F/S and experiment apparatus.

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This paper investigates friction characteristics of the linear ball guides. Linear ball guides are generally used for guiding linear motions of feed drive systems. In this study, friction characteristics of the linear ball guides are measured by using a core-less linear motor. As a result of the mathematical analysis, it have been confirmed that the friction force of the guides can be measured as a thrust force command in the experimental system. Measurement tests were carried out for three sizes of guides, three types of greases, three types of pre-load, and with or without of retainer. Firstly, relationships between velocity and friction force are discussed. As the results, it is clarified that the relationship between velocity and friction force depends on the grease viscosity, and the diameter of rolling ball. Non-linear spring characteristics in microscopic region are also measured. As the results of the measurement, it can be said that the non-linear spring characteristics depend on the size of the ball, pre-load, and retainer. The differences of the non-linear spring characteristics have influence on the vibration dumping of step responses.

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Evaluation of the natural frequency and the natural mode of vibration of a bolted joint is particularly important to avoid the failure of the structure due to the resonance. The vibration characteristics of a bolted joint are largely influenced by such factors as the surface roughness of contact surfaces, the magnitude of axial bolt force, the arrangement of clamping bolts, etc. In this paper, natural frequencies of the bending vibration of a bolted joint with simple configuration are measured using strain gages mounted on the surface of test specimen, and the effects of surface roughness, axial bolt force and the bolt location are systematically investigated. Then, a numerical procedure is proposed to analyze the free vibration problem of a bolted joint, where the effects of interface stiffness due to surface roughness are incorporated into the finite element formulation. It is also presented that the computation efficiency for solving the eigen value problem concerned can be fairly improved by introducing selective reduced integration (SRI) scheme. The effectiveness of the numerical procedure proposed here is validated by experimental measurements of the natural frequencies of the first mode.

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The aim of the study is to establish the machining methods for the small-size irregular holes with high precision profile of finished surface by multi-stroke groove slotting. The groove slotting experiments are conducted by single-stroke and multi-stroke process and assisted by ultra sonic vibration. As the results, by the effect on decrease of cutting force due to the ultra-sonic vibration, it is able to improve finished surface of stainless steel SUS304 with better straightness and roughness. From the time response analysis, the tendency for the tool tip with large rake angel to plunge into the workpiece because of the low stiffness of tool tip and as a result the straightness of finished surface is degraded. It is difficult to improve the straightness of deep grooving with ten strokes slotting and same depth of cut per stroke due to the work hardening effect of SUS 304 and the stiffness of tool tip. However, the straightness of 6 μm by using the small width of cutting tool and the low stiffness tool is able to accomplish due to the keeping mechanism of ultra-sonic vibration to the cutting direction. From these results, the techniques for micro irregular slotting are established.

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This paper describes slide-bending formation of thin metal sheet by using an industrial robot. The formation of parts made of very thin sheets has become increasingly important following the miniaturization of industrial products. The thinning of sheet thickness causes several problems on the formability and accuracy of the products. In order to solve such problems in bending, one of the authors proposed a new method called a slide bending formation. However, in order to form more precise products, it is necessary to construct a system which can be controlled more precisely. The authors have made an automatic slide-bending formation system which consists of a force sensor, a CCD camera and an industrial robot. The slide-bending forming tool was mounted on the top of the robot. The reactive forces in the normal and the horizontal direction were measured by the force sensor attached on the wrist. The trajectory of the robot was controlled so that the reactive force was kept constant. The bending angle of the sheet was measured by the CCD camera. From the results of the experiment, it is shown that the larger the reactive force, the larger the bending angle of the thin metal sheet.

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Generally laser processing machines use mechanical stages or robot arms to positioning a laser beam. Such positioning systems have wide process area and great positioning accuracy. However its process speed is very slow. We have developed a fine laser processing equipment with high accuracy positioning as well as wide process area. Galvanometer scanners and fθ lens of large diameter using a shrink fitter made it possible to process with great accuracy across the wide area. In this paper, we examined the process accuracy of this equipment by measuring the marks processed by this equipment. And in order to examine the process quality across the wide process area, the surface of the process marks were measured with a stylus profilometer. In addition, we considered an influence of a decentering of each lens in the scanning lens unit on positioning accuracy of the laser spots and field curvature on an image plane.

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Diamond polishing tapes are commonly used for edge finishing of zirconia ferrules. There remains a problem that the diamond tape has too short tool life due to weak bonding strength. Then we propose a new method to make a diamond tape applying electrodeposited nickel foil method. This method is very useful to make a long metal foil continuously and commercially used for manufacturing of a copper foil. In order to improve the tensile strength of the foil, we performed composite electroforming utilizing glass fibers. It was confirmed that the concentration of abrasives could be increased by using Ni-electroplated diamond abrasives. A series of experiments to finish zirconia ferrules proved long tool life of the developed polishing tape.

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In maintenance work of large products and equipment, a manger usually dispatches jobs to individual works taking the worker's skill and training plan into consideration. However, jobs are becoming increasingly complex and difficult, personnel changes are more frequent. Therefore, it is difficult for the manager to remember individual workers' abilities completely, and computer support is needed to estimate the work completion time numerically and devise a work schedule in consideration of each worker's skill and training plan. In this paper, after the problem of work scheduling support is defined, a method of scheduling and simulating work tasks is proposed. The proposed method adopts an agent-based scheduling method to reflect each worker's experience and to handle the amount of On-the-Job Training (OJT) that is planned in the schedule. The simulation results show that the proposed method, in which the relationship between the schedule for fulfilling the due date and the schedule for maintaining workers' skills can be adjusted, is effective in decision support for managers.

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This paper proposes a computer system that simulates product life cycles dynamically. A feature of the system is its ability to restructure life cycles, by which an additional module for simulation is inserted into the system when needed. This allows users to carry out various assessments efficiently depending on their purposes. To do so, a prototype system on computer program was developed and it proved the system's effectiveness through application to an example life cycle of a product, a refrigerator. Especially, it was confirmed that the system is able to calculate environmental burdens in a time series depending on given product life cycles. In addition, the system was proved to carry out simulations additionally with consumers' buying activities on the market and manufacturers' revenues and expenditures. This system is also expected to increase the efficiency of developing such systems.

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